It is clear that group-living nonhuman primates recognize individuals, and classify those individuals according to socially-relevant information such as familiarity, kinship, age, sex, and species. Although field and laboratory studies have clarified the presence of these discriminative behaviors in macaque monkeys, and laboratory experiments have demonstrated some of the cues contributing to such discriminative capacities, the cognitive underpinnings of such capacities remain unknown. Memory for particular social characteristics has not been well studied. Furthermore, the monkey's ability to organize memory and the degree to which memory organization or capacity is affected by the nature of the stimulus (social, nonsocial, abstract) are still open questions. The proposed research uses laboratory experimental designs developed to study human and animal cognition to address questions of memory capacity and organization of memory with abstract stimuli, social stimuli, and nonsocial natural stimuli. The specific aims of the research are (1) to investigate memory capacities for social categories in macaque monkeys, (2) to investigate the nature of memory organization by macaque monkeys and to determine whether such organization changes when social stimuli are presented, and (3) to study serial list learning of social stimuli in macaque monkeys. The macaque monkey provides an excellent model for the human in terms of brain structure, organization, and behavior. The monkey has cells in the inferotemporal cortex which respond specifically to facial stimuli and to particular attributes of these stimuli. In humans, insult to the temporal cortex by stroke or accident can lead to visual agnosias in the form of failure to identify individuals or failure to be able to identify or classify nonsocial stimuli that fall into functional categories. To the extent that we can develop measures of the organization of monkey memory, we can develop experimental models of brain damage with monkeys that can lead to understanding of visual agnosias and additional cognitive deficits in victims of stroke and other neurological disease. The basic research proposed here, which is noninvasive in nature, will lead to specific understanding of cognitive organization and memory capacities in macaque monkeys that can be used to develop animal models of cognition and deficit in humans.